a C ( eritical groups within the population, provided the critical group is small enough to be homogeneous with respect to age, diet and those aspects of behavior that affect the doses received. Such a group should be representative of those individuals in the population expected to receive the highest dose. ICRP believes that it will be reasonable to apply the appropriate dose limit for members of the public to the mean dose of this group. The inate variability within an apparently homogeneous group "means that some members of ‘the critical group will receive doses somewhat higher than the dose limit. gen i,A eet . tle oe . ey « eR Ie ~ tetoa wat wit ees <9 ft TL he ESnove At the very low levels of : . aa lile “3 a st ee oe, 272. eee ' =risk tnplied,the‘healéh” coneeeannee di isLakedy to be minor whether the dose limit is marginally or substantially exceeded. tives,adhsimi tation‘of exposure.of whole -populations: is achieved partlyiceSo “by Limiting the’ individual doses and partly by limiting the number Padtagh ea Medes Decree os Satoh neva iss Boba ky Sate Teg et eadts teste alTots “of persons exposed. It is of the utmost importance toavoid actions ‘that may prove to be a seriovs hazard later, when correction may be OE FF ec Guipossible or” costly: PEEVE Neko le ee al ine SoReal The ICRP dose limits for individual members of the public are in Table #. tion is given. no- threshold, Using the linear dose-effect relationship and assuming the ICRP indicates that an annual exposure of active red marrow, averaged over each individual in the population, of 0.5 rem (corresponding to the annual dose limit for members of the public) might at equilibrium lead to an increased incidence of leukemia, at most, of about ten cases per year per million persons exposed. The genetic dose to the population should be kept to the minimum SN ‘ ! amount consistent with necessity and should certainly not exceed 5 ~— “~~ ney No maximum "“somatically significant’ dose for a populea-